[update] API for AttributeMapping. Add Deprecation.
[update] API for relationship mapping
[add] assignment policy enum
[fix] incorrect setter for relationship
[update] managed object deserialiser spec by assignment policy
[replace] assignment policy enum with real objects
[add] objects class conversion
[update] assignment policy api
[update] managed object deserialiser to assign via assignment policy usage
[implement] merge assignment
[update] merge spec
[reformat] assignment policy spec
[rename] FEMMerge to FEMExtension
[implement] replace policy
Merge branch 'feature/assign_policy' into develop